Process for the electrolysis of liquids.



J. BILLITER. PROGESS FOR THE ELEOTEOLYSIS OF LIQUIDS. APPLICATION I'ILEDAUG. a, 1908.

903,951 PatentedNov. 17, 1908.

Witnesses. Inventor.

UNITED STATES PATENT OFFICE.

JEAN BILLITi-TR, OF .\i t,-llICRSLI'IIHCN, GERNIAXY.

PROCESS FOR THE ELECTROLYSIS OF LIQUIDS.

fication of the electrolyte, for the purpose of better separating theproducts atthe anode and cathodefrom each other. Examples oil suchprocesses, which especially relate to the electrolysis of chlorids, havebeen described c. y. in German latents H116? and 191234. On the otherhand Le Sueur, llargreavcs and Bird, Carmichael and others have soughtto preventthe mixing ol the anode and cathode solutions by supplying thecathode-ehamber with electrolyte-solu tion from the anode, so that thesolution fed in flows in the opposite direction to the movement of the()II-ions. As is known, such arrangement of the tlow is not snflicientto prevent the electric transfer of the OH-ions to the anode. A moreett'ectual method of combating this is to cause the solution containingthe alkali to separate itself as a heavier layer from the anode oln tionabove itand to control the supply of fresh solution in such a mannerthat the com-cntration ot' chlorin ions in the layers next to the anodeis at a maximum. This arrangement l-iowever is also Insufficient alone.

A process, which seeks-to combine the advantages of the two methods ofworking above mentioned, has been described in German Patent 1912-34. Asin the bell cell process (German Patent H1187), however, there isrequired in the said patent, a motion of the lower layer, in order tomaintain the stratification or to continuouslyreform the separatinglayer. The circulation of the solution must therefore take place atarelatively rapid rate as in the bell cell process.

Bty this means, however, the concentration he lyes which can be obtainedwith good yields would again set an upper limit fairly soon. Moreover,cells of this kind are very sensitive to variations of pressure in thegas chamber, such as frequently occur in technical work, since theoscillations of the liquid caused thereby involve destruction ofSpecification of Letters Patent.

Application filed August 3. 1908.

by this means is considerable.

Patented Nov. 17, 1908.

Serial No. 446.720.

the stratification. \Yith the same'current, however. higherconcentrations. of the alkali can be obtained and the method ofoperation is made much more convenient and simple, it the.stratilication is maintained without. lateral motion of the layers ofliquid. and it', using. closed cells (without overflow) only thelowermost, densest layer, which contains lnost' alkali, is employed forfeeding the cathode chamber. This object can be attained by making acell with a horizontal arrangement that maintains a hil'illlllftlllOllby heating from above, which has the supply of feed solution at thelevel of the heating pipes and in which the cathmle-chamber is tedsolely by the passage through the diaphragm ol t-hc heaviestlayer whichis richest in alkali, lying directly above the dia phragm and containedin the diaphragm.

Extended technical investigations on a large. scale have shown that thestratification. is produced more advantageously by heating the solutionwhich is in the neighborhood of theupper electrode and which is toseparate itself as the upper layer, instead of allowing it to becomeweak. The heating is preferably affected by heating pipes, which incontradistinction to all known arrangements are arranged above the upperelectrode. when this is mounted horizontally, and at the level of thiselectrode when it is arranged vertically (for example in the form otvertical downwardlyextending rods). or by means ol steam whichisconducted into the space above the surface of the liquid. Theadvantage which is obtained Hot concentrated salt-solution can beclectrolyze d lat I the upper electrode, so that the resistance of thebath' is lower and the current density (with the same pressure) ishigher, and the life of the electrodes is increased since they aregenerally more rapidly destroyed 'in dilute solutions, in cases in whichsoluble gases are given olt' at the upper electrode (for example in theelectrolysis of the chlorids of alkalies) their solubility is decreasedby the elevated temperature and the interaction between the dissolvedgases and the products of electrolysis in the lower heavy layer isreduced. and so on. By means of a cell constructed as hereinafterdescribed from this point of view, it is possible to employ the heaviestlayer containing the greatestauiount of alkali alone for feeding thecathmle-chamberarranged beneath the diaphragm, this being efl"ectedsolely by the supply through the diaphragm.

One constructional form of the improved cell is shown in theaccompanying drawing. 5 I For receiving the solution, a tank 2 of heavyiron plate lined with cement 1 is employed. The heating pipes 14 and thesupply pipe 17 for the solution to be fed in are arranged at the levelof the upper electrodes 9 for the purpose of maintaining thestratification and to enable the solution sup plied to be broughtdirectly to the maximum temperature in the tank by means of the heatingpipes, in order that their chlorinions shall have the highest ossiblevelocity of diffusion. The, horizontally mounted d iaphragm 4 liesdirectly on the wire net-work 3'forming the cathode- In order to provideroom for the easy escape of the gases gener- 20 ated on this network-,-Iicarriers 16 are employed which are mounted on the one hand on the ironbottom of the "tank and which support the slightly corrugated wirenetwork at several places, which would other wise bend under the load ofthe conten'tstof the bath. 'Av double bottom is thus. pro duced, throughwhich the gases pass-linorder'" to be conducted away through abranehjiipe or the like, while the lye runs away at the 80 bottom... Thecarriers can .be made of metal and can then simultaneously serve asterminals for the supply of the current.

The rapidity of the flow through the diaphragm can obviously beregulated by the composition and thickness of the latter. If thethickness and composition of the -diaphragm are already chosen, therapidity of flow can be varied by adjusting the height of the liquid inthe interior of the tank. 40 Since however the permeability of the diaphragms decreases somewhat in the course of time by the impurities whichdeposit themselves thereon, an arrangement can be. adopted for theuniform feeding of the cathode-chamber, which permits a smaller orgreater degree of vacuum to be produced in the lower space or chamber,in order to increase the flow oflye through the .diaphragm. For thispurpose, the run away pipe 11 is provided with abranch 12, through whichthe gas :can be drawn off. This branch pipe preferably extends upwardsat an inclination in order that the currentof shall not carry away anylye with it. Any drops of liquid which maybe carried along with the gasmay be kept back by transversely mounted wire grids 18; by this means itis also possible to insure that any explosions of gas which may takeplace ex- 'ternally shall not extend into the interior of the bath. Aslight vacuum can be produced in a very simple manner by causing thebranch pipe12 to extend upwards, thus producing the vacuum byth'e'suctiomefiect liquid' which contains the greatest amount of theprodugts of electrolysis at the cathode. The siiidjarrangement thereforegives the highest concentration of the lye with the best yield. Theapparatus can obviously be also employed for the electrolysis of otherthan .chlorid solutions, and. the lower electrodechamber under specialconditions may form the anode-chamber.

\Vhat I claim is 1- 1. The process of electrolyzing liquids, whichcomprises feeding the liquid to the upper one of electrode chambers atdifferent levels and separated by a diaphragm and heating the liquid inthe upper chamber.

2. The process of electrolyzing liquids, which comprises feeding theliquid to the upper one of superposed electrode chambers separated by adiaphra 'm and heating the electrolyte at or above the electrodes insaidchambers.

, 3. The process of electrolyzing liquids which'comprises feeding theliquid on to a heated surface contained in the upper one of superposed,diaphragm separated, .electrode chambers at or above the level of theelectrodesin said chainber.

A. The process of. electrolyzing liqpqids which compriscs'feedingthediquid to he dipper one of two, diaphragm scpajlfit al, gelectrodechambers at difi'erentdevels, heat-- ing the liquid at anupper level inthe upper l1 chamber and maintaining a suction'in. the v lower chamberbeneath the rhaphragm to control the movement throiigh the diaphragm.

The process of electrolyzing liquids, which comprises feeding the liquidto a heated surface in the upper one of two superposed diaphragmseparated,electrode cham-i hers and controlling the withdrawing ofthegas generated from the lower chamber beneath the diaphragm at a greaterrate than the rate of formation of said gas to maintain a suctionbeneath the diaphragm.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

JEAN BILLITER. Witnesses:

ALBERT B. GREEN, WILHELM AnnNnRo'rH.

